Devices and techniques relating to landfill gas extraction

ABSTRACT

Devices and techniques related to landfill gas extraction are disclosed. A technique for controlling extraction of landfill gas from a landfill through a gas extraction system is described. The method may include measuring a plurality of values indicating conditions associated with the landfill; computing, based at least in part on the plurality of values and on a model of the landfill, a predicted future state of the landfill; determining, based at least in part on the predicted future state of the landfill, one or more control parameters for one or more respective control devices configured to control operation of the gas extraction system; applying the one or more control parameters to the one or more respective control, and with the one or more control devices, controlling extraction of the landfill gas from the landfill based, at least in part, on the one or more respective control parameters.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a continuation of and claims priority under 35U.S.C. § 120 to U.S. patent application Ser. No. 16/831,131, titled“Devices and Techniques Relating to Landfill Gas Extraction,” filed Mar.26, 2020 which is a continuation of and claims priority under 35 U.S.C.§ 120 to U.S. patent application Ser. No. 15/456,936, titled “Devicesand Techniques Relating to Landfill Gas Extraction,” filed Mar. 13,2017, which is a continuation of and claims priority under 35 U.S.C. §120 to U.S. patent application Ser. No. 14/532,807 (U.S. Pat. No.10,029,290, issued Jul. 24, 2018), titled “Devices and TechniquesRelating to Landfill Gas Extraction,” filed Nov. 4, 2014, which claimsthe benefit under 35 U.S.C. § 119(e) of U.S. Provisional ApplicationSer. No. 61/899,828, titled “In-Situ Control Mechanisms for Landfill GasExtraction Wells” and filed on Nov. 4, 2013, and U.S. ProvisionalApplication Ser. No. 61/913,628, titled “System and Methods forOptimizing Landfill Gas Extraction” and filed on Dec. 9, 2013, each ofwhich are hereby incorporated by reference herein in their entireties.

BACKGROUND Technical Field

The devices and techniques described herein relate to controllingextraction of gas from landfills.

Discussion of the Related Art

Landfills typically produce landfill gas as a result of decompositionprocesses occurring in the waste, and methane is often a component ofthis landfill gas. In order to reduce emissions of methane and othercontaminants in landfill gas, the landfill sites are typically cappedwith a layer of cover material and gas extraction systems are installedto pull landfill gas out before it can penetrate the cover layer andescape. At larger sites, these gas extraction systems can consist of aplurality of vertical and horizontal wells drilled into the landfill,which are connected with piping to one or more vacuum sources. The coverlayer prevents gas from freely escaping, while the vacuum in theextraction wells pulls landfill gas into the collection system. Aconventional landfill gas extraction well typically has a manual valvethat adjusts the localized vacuum pressure in that well, as well as aset of ports for sampling the gas characteristics with a portable gasanalyzer. Landfill gas is most often disposed of in a flare, processedfor direct use, or used to power electricity generation equipment (suchas generators or gas turbines).

SUMMARY

According to an aspect of the present disclosure, a method forcontrolling extraction of landfill gas from a landfill through a gasextraction system is provided, the method comprising: measuring aplurality of values indicating conditions associated with the landfill;with at least one computing device, computing, based at least in part onthe plurality of values and on a model of the landfill, a predictedfuture state of the landfill; determining, based at least in part on thepredicted future state of the landfill, one or more control parametersfor one or more respective control devices configured to controloperation of the gas extraction system; applying the one or more controlparameters to the one or more respective control devices of the gasextraction system; and with the one or more control devices, controllingextraction of the landfill gas from the landfill based, at least inpart, on the one or more respective control parameters.

According to another aspect of the present disclosure, an apparatus forcontrolling extraction of landfill gas from a landfill through a gasextraction system is provided, the apparatus comprising: one or moreprocessors; and at least one computer-readable storage medium storinginstructions which, when executed by the one or more processors, causethe apparatus to perform a method. The method includes controlling aplurality of sensors to measure a plurality of values indicatingconditions associated with the landfill; predicting, based at least inpart on the plurality of values and on a model of the landfill, a futurestate of the landfill; determining, based at least in part on thepredicted future state of the landfill, one or more control parametersfor one or more respective control devices of the gas extraction system;controlling application of the one or more control parameters to the oneor more respective control devices of the gas extraction system; andcontrolling the one or more control devices to control extraction of thelandfill gas from the landfill based, at least in part, on the one ormore respective control parameters.

According to another aspect of the present disclosure, a gas extractionsystem for controlling extraction of landfill gas from a landfill isprovided, the system comprising: at least one vacuum source; one or morecontrol devices disposed in well piping and configured to control flowrates of the landfill gas through the well piping; one or more wellscoupled to the at least one vacuum source through the well piping andthrough the one or more control devices disposed in the well piping; andone or more processors. The one or more processors are configured tomeasure a plurality of values indicating conditions associated with thelandfill; predict, based at least in part on the plurality of values andon a model of the landfill, a future state of the landfill; determine,based at least in part on the predicted future state of the landfill,one or more control parameters for the one or more respective controldevices; and apply the one or more control parameters to the one or morerespective control devices, wherein the one or more control devices areconfigured to control extraction of the landfill gas from the landfillbased, at least in part, on the one or more respective controlparameters.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects and embodiments will be described with reference to thefollowing figures. It should be appreciated that the figures are notnecessarily drawn to scale. For purposes of clarity, not every componentmay be labeled in every drawing. In the drawings:

FIG. 1 is a sketch illustrating a landfill gas extraction system,according to some embodiments;

FIG. 2 is a block diagram illustrating an in situ control mechanism forlandfill gas extraction, according to some embodiments;

FIG. 3 is a block diagram illustrating a gas analyzer of an in situcontrol mechanism for landfill gas extraction, according to someembodiments;

FIG. 4 is a block diagram illustrating a controller of an in situcontrol mechanism for landfill gas extraction, according to someembodiments;

FIG. 5 is a block diagram illustrating an example of a control systemfor controlling landfill gas extraction, according to some embodiments;

FIG. 6 is a block diagram illustrating an example of a feedback-based,predictive system for controlling landfill gas extraction, according tosome embodiments;

FIG. 7 is a flow diagram illustrating another example of afeedback-based, predictive system for controlling landfill gasextraction, according to some embodiments;

FIG. 8 is a sketch of an example of zones of influence of wells in alandfill;

FIG. 9 is a sketch of another example of zones of influence of wells ina landfill;

FIG. 10 is a flowchart of a method for controlling extraction oflandfill gas from a landfill through a gas extraction system, accordingto some embodiments; and

FIG. 11 is a block diagram of an exemplary computer system in whichaspects of the present disclosure may be implemented, according to someembodiments.

DETAILED DESCRIPTION

Conventional techniques for controlling extraction of landfill gas aresometimes imprecise and inefficient. When such techniques are used, thegas extracted from a landfill may not have the desired properties (e.g.,the energy content of the extracted gas may be lower than a desiredenergy content, the composition of the extracted gas may differ from adesired composition, etc.). In some cases, conventional techniques mayeven be counter-productive (e.g., such techniques may destroy some orall of the bacteria that convert decomposing waste into methane, therebyreducing the energy content of the landfill gas, or may result inemission of high levels of methane into the atmosphere).

The inventors have recognized and appreciated that controllingextraction of landfill gas based on a predictive model of the landfillmay overcome at least some of the deficiencies of conventional landfillgas extraction techniques. For example, controlling extraction oflandfill gas based on a predictive model of the landfill may increaseprecision and/or efficiency of the gas extraction process, therebyfacilitating extraction of landfill gas having desired properties. Asanother example, controlling extraction of landfill gas based on apredictive model of the landfill may reduce the landfill's environmentalimpact (e.g., by reducing the amount of harmful and/or foul-smelling gasemitted into the atmosphere). In some embodiments, the performance ofthe gas extraction system may be enhanced by adjusting the system'scontrol settings in real time or at frequent intervals (e.g., hourly ordaily). In some embodiments, the performance of the gas extractionsystem may be enhanced by training the predictive model based ondifferences between the landfill state predicted by the model and thelandfill state actually observed. In some embodiments, the performanceof the gas extraction system may be enhanced by modeling interactionsbetween/among two or more wells.

The aspects and embodiments described above, as well as additionalaspects and embodiments, are described further below. These aspectsand/or embodiments may be used individually, all together, or in anycombination, as the application is not limited in this respect.

This disclosure describes devices and techniques for controllinglandfill gas extraction. FIG. 1 illustrates a landfill gas extractionsystem 100, according to some embodiments. In some embodiments, alandfill gas extraction system may include one or more gas extractionwells 102 coupled to one or more wellheads 104. In some embodiments,each wellhead may be in fluid communication with a single, correspondingwell. In some embodiments, the landfill gas extraction system 100 mayinclude a gas extraction piping system 108 coupling the well(s) 102 to agas collection system 110, and one or more In Situ Control Mechanisms106 for controlling extraction of the landfill gas through the well(s)102 and gas extraction piping system 108 to the gas collection system110. In some embodiments, gas collection system 110 may supply theextracted landfill gas to a gas-to-energy power plant 112, which mayconvert the landfill gas into electrical power (e.g., by burning thelandfill gas to turn the rotor of a generator or turbine). In someembodiments, the In Situ Control Mechanism(s) 106 may operate (e.g.,individually, in concert with each other, and/or under the control of acontroller) to improve gas extraction efficiency and/or to control theextraction process for a variety of desired outcomes. In someembodiments the controller may be located remote from the In SituControl Mechanisms. (Such a remotely located controller is not shown inFIG. 1 , but is shown in FIG. 5 and discussed below.)

It should be appreciated that an In Situ Control Mechanism, as describedherein, may control one or more parameters associated with a well, butis not a requirement that all other In Situ Control Mechanisms bephysically located at that well. The In Situ Control Mechanism(s) may bedisposed at any suitable location(s). In some embodiments, each In SituControl Mechanism may be coupled to a single, corresponding well. Insome embodiments, an In Situ Control Mechanism may be coupled to one ormore wells. In some embodiments, some or all of the gas extraction wellsin a landfill gas extraction system may be outfitted with an In SituControl Mechanism 106, as depicted in FIG. 1 . In some embodiments, anIn Situ Control Mechanism 106 may be positioned at or adjacent to one ormore junction points in the gas extraction piping system 108 (headerjunctions, or leachate junctions, or others) to control the performanceof an entire section of piping. In some embodiments, an In Situ ControlMechanism 106 may be positioned between the gas extraction well 102 andthe gas collection system 110 such that gas coming from the well flowsthrough the In Situ Control Mechanism 106 on its way to the rest of thecollection system. The In Situ Control Mechanism 106 may be installedpermanently in a suitable location (e.g., in, on, adjacent to, and/ornear a well and/or gas extraction piping), or may be moved from locationto location (e.g., well to well) over time.

A block diagram of some embodiments of an In Situ Control Mechanism 200is presented in FIG. 2 . In some embodiments, an In Situ ControlMechanism may include one or more mechanisms configured to control theflow of landfill gas from one or more wells to gas collection system 110through gas extraction piping system 108. Any suitable flow-controlmechanism 206 may be used, including, without limitation, a valve (e.g.,a solenoid valve, latching solenoid valve, pinch valve, ball valve,butterfly valve, ceramic disc valve, check valves, choke valves,diaphragm valves, gate valves, globe valves, knife valves, needlevalves, pinch valve, piston valve, plug valve, poppet valve, spoolvalve, thermal expansion valve, pressure reducing valve, sampling valve,safety valve) and/or any other suitable type of flow-control mechanism.

In some embodiments, an In Situ Control Mechanism may include one ormore actuation devices configured to control operation of the one ormore flow-control mechanisms (e.g., to open a flow-control mechanism,close a flow-control mechanism, and/or adjust a setting of aflow-control mechanism). In some embodiments, an In Situ ControlMechanism may include a controller 204 configured to determine thesettings to be applied to the one or more flow-control mechanisms (e.g.,via the actuation devices), and/or configured to apply the settings tothe one or more flow-control mechanisms (e.g., via the actuationdevices). In some embodiments, the settings to be applied to the one ormore flow-control mechanisms (e.g., via the actuation devices) may bedetermined remotely and communicated to the In Situ Control Mechanism(e.g., by a remotely located controller) using any suitablecommunication technique, including, without limitation, wirelesscommunication, wired communication, and/or power line communication.

In some embodiments, an In Situ Control Mechanism may include one ormore sensor devices configured to sense one or more attributesassociated with the landfill, including, without limitation, attributesof the landfill, attributes of the landfill gas, attributes of an areaadjacent to the landfill, and/or attributes of the landfill's gasextraction system. In some embodiments, the In Situ Control Mechanismmay include one or more actuation devices configured to controloperation of the one or more sensor devices (e.g., to activate a sensordevice, deactivate a sensor device, and/or collect data from the sensordevice). In some embodiments, an In Situ Control Mechanism may include acontroller 204 configured to determine the settings (e.g., controlsignals) to be applied to the one or more actuation and/or sensordevices, configured to apply the settings to the one or more actuationand/or sensor devices, and/or configured to collect data (e.g.,measurements) obtained by the one or more sensor devices. In someembodiments, the settings to be applied to the one or more actuationand/or sensor devices may be determined remotely and communicated to theIn Situ Control Mechanism (e.g., by a remotely located controller) usingany suitable communication technique, including, without limitation,wireless communication, wired communication, and/or power linecommunication. In some embodiments, the In Situ Control Mechanism maycommunicate the one or more sensed attributes associated with thelandfill (e.g., to a remotely located controller).

In some embodiments, the one or more sensor devices may include a GasAnalyzer 202. In some embodiments, a Gas Analyzer 202 may collect asample of landfill gas from the gas extraction piping 208 through aninput port 210, determine (e.g., compute, measure and/or sense) one ormore characteristics of that gas, and/or report the one or morecharacteristics of the gas to a controller (e.g., local controller 204and/or a remotely located controller). In some embodiments, the GasAnalyzer may determine the gas temperature, pressure, flow rate,humidity, density, gas composition (partial pressure or concentration ofmethane, oxygen, carbon dioxide, carbon monoxide, hydrogen sulfide,and/or any other suitable gas) and/or any other characteristics of thelandfill gas coming from the gas extraction well(s) upstream from thelocation where the In Situ Control Mechanism is installed. The gascharacteristics may be sampled once in each reading, or may be sampledmany times and statistics about the distribution of values may bedetermined. The gas characteristics may be continuously determined, orthey may be determined at discrete time intervals. In some embodiments,the Gas Analyzer may analyze gas in the main flow of landfill gas (e.g.,within gas extraction piping 208). In some embodiments, the Gas Analyzermay draw a small sample of gas into a separate chamber for analysis. Insome embodiments, certain parameters (for example flow rate, pressure,temperature, humidity, and the like) may be measured in the main gasstream (e.g., may be measured by sensors disposed directly withinextraction gas piping), and others may be analyzed in a separatechamber.

In order to improve measurement accuracy, measurement resolution,measurement repeatability, sensor lifetime, and/or sensor reliability, asample of gas from the well may be pre-treated before analysis, whichpre-treatment may include heating, cooling, drying, and/or any othersuitable pre-treatment processing (e.g., through forced condensation,passing through a desiccant, or any other suitable technique), filteredto remove particles, filtered to remove contaminants or other chemicals,pressurized, de-pressurized, and/or otherwise treated before beinganalyzed. After analyzing and reporting gas characteristics (e.g., tolocal controller 204 and/or to a remotely located controller), the GasAnalyzer may purge the gas sample from the chamber and vent it to theatmosphere, or return it to the main gas flow. In some embodiments, theanalyzed gas sample may be purged prior to reporting the gascharacteristics to a controller.

One embodiment of a Gas Analyzer 300 utilizing pre-treatment mechanismsas described above is illustrated in FIG. 3 . In the Gas Analyzer 300 ofFIG. 3 and other arrangements not explicitly described here, a smallsample of landfill gas may be taken into the Gas Analyzer through inputport 310 (e.g., from the main flow of landfill gas in gas extractionpiping 308 between the gas extraction well and the gas collectionsystem) and sent through a drying element 312 and a series of one ormore flow-control mechanisms (e.g., valves) before entering the gasanalysis sample chamber 302. In some embodiments, at the beginning andend of a gas measurement cycle, both valves 316 and 318 are in theclosed state. Valve 316 may be opened and the pump 314 may be turned onin order to draw a sample of landfill gas through the drying element 312and into the gas analysis sample chamber 302 for analysis. At the end ofa measurement cycle, the pump 314 may be turned off and valve 316 may beclosed to stop the flow of gas into the sample chamber 302. In someembodiments, the gas sample may be purged from sample chamber 302 byopening valve 318. Under typical operating conditions, the gascollection system and gas extraction well(s) may be at negative pressure(i.e., operating under vacuum conditions) relative to atmosphericpressure, such that opening valve 318 may pull ambient air through theGas Analyzer 300 to purge the sample chamber 302 of landfill gas. Insome embodiments, one or more valves of Gas Analyzer 300 may be toggledand a pump (e.g., pump 314) may be activated to force purge samplechamber 302 with ambient air. Forced purging may be beneficial when oneor more wells upstream from Gas Analyzer 300 are operating underpositive pressure relative to atmospheric pressure (e.g., because thegas extraction system's vacuum is off-line or because the one or morewells are under-extracted). For example, forced purging may be aneffective technique for clearing condensate from the Gas Analyzer'stubes and/or for clearing sample gas from sample chamber 302 in caseswhere the upstream well(s) are operating under positive pressure.(Although not shown, one of ordinary skill in the art would understandthat a valve may be placed between pump 314 and input port 310, and thatsample chamber 302 may be force purged by closing this valve and byopening valves between pump 314 and atmospheric port 320.) After purgingthe gas sample from Gas Analyzer 300, valve 318 may be closed to stopatmospheric air from leaking into the gas collection system.

Configurations that perform a similar function to the embodiment of FIG.3 and which, while not described explicitly here, are within the scopeof the present disclosure. For example, the pump 314 may be placed aftervalve 316, or after the gas analyzer sample chamber 302, or the dryingelement 312 may be moved to a different point in the flow path.Similarly, the functionality provided by valve 316 and the pump 315 maybe consolidated by the use of a sealed pump design (e.g., a peristalticpump). An additional valve may be added after the gas analyzer (e.g., ina port 322 coupling the sample chamber 302 to the gas extraction piping308), for additional control or to prevent backflow into the samplechamber. Additionally, the Gas Analyzer may be outfitted with additionalmodules to provide other pre-treatment of the gas in addition to or inalternative to drying (for example, particle filtering, removal ordeactivation of hydrogen sulfide or other chemicals, etc.).

In some embodiments, the flow-control mechanism(s) of Gas Analyzer 300may include solenoid valves, latching solenoid valves, pinch valves,ball valves, butterfly valves, ceramic disc valves, check valves, chokevalves, diaphragm valves, gate valves, globe valves, knife valves,needle valves, pinch valves, piston valves, plug valves, poppet valves,spool valves, thermal expansion valves, pressure reducing valves,sampling valves, safety valves, and/or any other type of flow-controlmechanism.

In some embodiments, the Gas Analyzer may utilize non-dispersiveinfrared (NDIR) sensors, catalytic beads, electrochemical sensors,pellistors, photoionization detectors, zirconium oxide sensors, thermalconductivity detectors, and/or any other sensing technology. Flow ratemay be measured by a pressure differential across a venturi, orificeplate, or other restriction to the flow of gas; by pitot tube,mechanical flow meter, heated wire or thermal mass flow meter, and/orusing any other suitable technique. Temperature may be measured with athermocouple, a negative or positive temperature coefficient resistor,capacitor, inductor, a semiconducting device, and/or using any othersuitable technique. Temperature may be measured inside the well, in themain gas flow from the well to the collection system, inside a samplingchamber, outside of the control mechanism (e.g., ambient atmospherictemperature), and/or at any other suitable point. Temperature, pressure,gas composition, and/or other readings from different points within thegas extraction well, the In Situ Control Mechanism, and/or the gascollection system may be used in conjunction with each other to obtain amore complete analysis of the operating state of the landfill gascollection system.

FIG. 4 shows a controller of an In Situ Control Mechanism, according tosome embodiments. In some embodiments, the Controller 400 of an In SituControl Mechanism may include functional blocks as indicated in FIG. 4 .In the embodiment of FIG. 4 , the Controller 400 includes a SignalProcessing Module 418, a Data Storage Device 420, a Real Time ClockModule 422, a Wireless Communication Module 416, and/or a Flow-ControlMechanism Actuator 412 (e.g., valve drive buffer) for providing acontrol signal to the Flow-Control Mechanism 406. Other embodiments mayuse only parts of this implementation, while others may add additionalfunctional modules for supporting functions. For example, in someembodiments, the Controller of an In Situ Control Mechanism may beimplemented using a one or more processors as described below.

In some embodiments, the Controller 400 of the In Situ Control Mechanismmay use data about environmental conditions in and around the landfill(e.g., in and around the gas extraction well upon which the In SituControl Mechanism is installed) to determine the settings to be appliedto the flow-control mechanism. In some embodiments, a remotely-locatedcontroller may use the environmental data to determine the settings tobe applied to the flow-control mechanism, and may communicate thosesettings to the In Situ Control Mechanism. The environmental data mayinclude information about parameters including, but not limited toatmospheric pressure, ambient temperature, wind direction, wind speed,precipitation, and/or any other suitable environmental parameter. The InSitu Control Mechanism may use information from other sensors placed inor around the gas extraction well, including, without limitation,subsurface temperature probes, subsurface moisture probes, measurementsof the chemical and/or biological processes (for example, pHmeasurements, tests for the presence of other chemicals or biologicalby-products, etc.) occurring in the section of waste that is in thevicinity of the gas extraction well, and/or any other suitableinformation.

In some embodiments, the Controller 400 of the In Situ Control Mechanismmay use the current data about the gas characteristics and/orenvironmental parameters, and/or it may incorporate historical dataabout the performance of the gas extraction well to determine thesettings to be applied to the Flow-Control Mechanism. In someembodiments, a remotely-located controller may use the gas data,environmental data, and/or historical data to determine the settings tobe applied to the flow-control mechanism, and may communicate thosesettings to the In Situ Control Mechanism. The In Situ Control Mechanismmay, in some embodiments, incorporate past and/or present data about gasproduction into one or more predictive models and may use the predictivemodel(s) to determine the modulation of the Flow-Control Mechanismstate.

In some embodiments, the Signal Processing Module 418 takes gascharacteristics data from the Gas Analyzer 402 and converts it into aform that can be interpreted by the Computing Core 414. This may involvea interpreting a serial digital data stream via a serial parsingalgorithm, a parallel parsing algorithm, analog signal processing (forexample, performing functions on analog signals like filtering, addingor removing gain, frequency shifting, adding or removing offsets, mixingor modulating, and the like), digital signal processing (digitalfiltering, convolution, frequency shifting, mixing, modulating, and thelike), analog-to-digital or digital-to analog conversion, and/or anyother suitable signal processing technique that will be recognized byone of ordinary skill in the art. In some embodiments, the Data StorageDevice 420 may include any volatile and/or non-volatile memory element,including but not limited to flash memory, SD card, micro SD card, USBdrive, SRAM, DRAM, RDRAM, disk drive, cassette drive, floppy disk, cloudstorage backup, and/or any other suitable computer-readable storagemedium. The Data Storage Device may serve as a data recovery backup, orit may hold data for temporary intervals during the calculation ofcontrol signals. The Data Storage Device may be removable, or it may befixed.

In some embodiments, the Real Time Clock Module 422 may include anycircuit and/or functional module that allows the Computing Core toassociate the results of a gas analyzer reading with a date or time(e.g., a unique date or time stamp).

In some embodiments, the Wireless Communication Module 416 may include,but is not limited to: a radio transceiver (AM or FM, or any othertype), television, UHF, or VHF transceiver, Wi-Fi and/or other 2.4 GHzcommunication module, cellular chipset (2G, 3G, 4G, LTE, GSM, CDMA,etc.), GPS transmitter, satellite communication system, and/or any othersuitable wireless communication device. The Wireless CommunicationModule may have an integrated antenna, and/or an external one. TheWireless Communication Module may transmit, receive, and/or have two-waycommunication with a central source and/or be capable of point-to-pointcommunication with another module. In some embodiments, the WirelessCommunication Module may include a 2G chipset that allows the In SituControl Mechanism to connect to existing telecommunicationsinfrastructure.

In some embodiments, the Computing Core 414 may include, but is notlimited to: a microprocessor, a computer, a microcontroller, a fieldprogrammable gate array (FPGA), an application specific integratedcircuit (ASIC), a digital signal processor (DSP), an analog computer orcontrol system, and/or any other suitable computing device. In someembodiments, the Computing Core may have integrated Analog-to-Digitalconverters, pulse width modulation detectors, edge detectors, frequencydetectors, phase detectors, amplitude detectors, demodulators, RMS-DCconverters, rectifiers, and/or other suitable signal processing modules.

In some embodiments, the Flow-Control Mechanism Actuator 412 (e.g., avalve drive buffer) may include any circuit that can translate commandsfrom the Computing Core into an appropriate actuation signal (e.g.,driving signal) for the Flow-Control Mechanism 406. In some embodiments,translating commands from the Computing Core may comprise analog signalprocessing on a voltage (for example, adding/removing gain, offset,filtering, mixing, etc.), analog signal processing on a current control(for example, conversion to a 4-20 mA control loop, increasing outputcurrent drive capability), pulse width modulating a digital signal,digital signal processing, digital-to-analog or analog-to-digitalconversion, and/or any other suitable techniques.

In some embodiments, the Flow-Control Mechanism 406 of the In SituControl Mechanism may comprise a solenoid valve, latching solenoidvalve, pinch valve, ball valve, butterfly valve, ceramic disc valve,check valve, choke valve, diaphragm valve, gate valve, globe valve,knife valve, needle valve, pinch valve, piston valve, plug valve, poppetvalve, spool valve, thermal expansion valve, pressure reducing valve,sampling valve, safety valve, and/or any other suitable type offlow-control mechanism. The Flow-Control Mechanism may have two or morediscrete operating states, or it may provide continuous adjustment ofthe operating state (e.g., valve position) for fine control of operatingpressure, temperature, flow, gas characteristics, etc.

In some embodiments, the In-Situ Control Mechanism may modulate theFlow-Control Mechanism to achieve any number of desired outcomes, or itmay determine the state of the Flow-Control Mechanism based on anoptimization and/or prioritization of multiple output parameters. Someexamples of control schemes might include, but are not limited to:

-   -   Modulation of the flow-control mechanism to maintain and/or        obtain a constant vacuum pressure in the gas extraction well (in        spite of varying atmospheric pressure, temperature, and/or        varying rates of gas generation, etc.);    -   Modulation of the flow-control mechanism to maintain and/or        obtain a constant flow rate of landfill gas from the extraction        well;    -   Modulation of the flow-control mechanism to control the flow        rate of landfill gas from the extraction well;    -   Modulation of the flow-control mechanism to maintain and/or        obtain a constant percentage of any of the constituent gases        (including but not limited to methane, carbon dioxide, oxygen,        nitrogen, etc.) in the landfill gas coming from the extraction        well;    -   Modulation of the flow-control mechanism to control (e.g.,        increase or decrease) the concentration of any of the        constituent gases in the landfill gas coming from the extraction        well;    -   Modulation of the flow-control mechanism to control (e.g.,        increase and/or decrease) the energy content of the landfill gas        (e.g., increase the total quantity of methane extracted in a        given period of time, etc.) coming from the extraction well;    -   Modulation of the flow-control mechanism to control the total        volume of the landfill gas (e.g., increase the total quantity of        landfill gas extracted in a given period of time, etc.) coming        from the extraction well;    -   Modulation of the flow-control mechanism to increase the rate of        extraction during periods of increased energy demand (e.g.,        increasing generation during the peaks of real time, hourly,        daily, weekly, monthly, or seasonal electricity prices);    -   Modulation of the flow-control mechanism to decrease the rate of        extraction during periods of reduced energy demand (e.g.,        reducing generation during the lows of real time, hourly, daily,        weekly, monthly, or seasonal electricity prices);    -   Modulation of the flow-control mechanism to control (e.g.,        maintain, improve, and/or establish) the long term stability of        the biochemical decomposition processes (aerobic or anaerobic        digestion, etc.) occurring within the section of waste that is        in the vicinity of the gas extraction well;    -   Modulation of the flow-control mechanism to control (e.g.,        increase and/or decrease) the rates of decomposition occurring        within the section of waste that is in the vicinity of the gas        extraction well;    -   Modulation of the flow-control mechanism to match the operating        parameters or limitations of the gas collection system;    -   Modulation of the flow-control mechanism to prevent or        extinguish underground fires or other potentially dangerous        events occurring within the section of waste that is in the        vicinity of the gas extraction well;    -   Modulation of the flow-control mechanism to mitigate emission of        odors; Modulation of the flow-control mechanism to control        (e.g., reduce) emissions of landfill gas or components of        landfill gas (H₂S, methane, etc.) in the vicinity of the gas        extraction wells;    -   Modulation of the flow-control mechanism to control (e.g.,        reduce) gas losses into the atmosphere;    -   Modulation of the flow-control mechanism to control (e.g.,        maintain, improve, and/or establish) compliance of the gas        extraction system with local, state and/or federal regulations;        and/or    -   Modulation of the flow-control mechanism to reduce damage to an        engine, turbine, or other energy generation equipment from        contaminants emanating from the vicinity of a gas extraction        well.

In some embodiments, some or all of the gas extraction wells and/orpiping junction points in a landfill may be outfitted with In-SituControl Mechanisms to form at least a portion of a control system forcontrolling gas extraction across the entire landfill or a set of wellswithin the landfill (the “landfill under control”). One embodiment ofsuch a control system is shown in FIG. 5 .

FIG. 5 shows a control system 500 for a landfill gas extraction system,according to some embodiments. In some embodiments, control system 500may include one or more In Situ Control Mechanisms 506 configured tocontrol gas flow in a gas extraction system in a landfill under control520. In some embodiments, control system 500 may include a controllermodule 504 for modeling aspects of the landfill under control, forcommunicating with the In Situ Control Mechanisms, and/or forcontrolling the operation of the In Situ Control mechanisms. In someembodiments, controller module 504 may be implemented on one or morecomputers located remotely from the In Situ Control Mechanisms (e.g., ona centralized computer or in a distributed computing environment). Insome embodiments, controller module 504 may execute a multitaskingprogram with different tasks configured to control the operation ofdifferent In Situ Control Mechanisms and/or to communicate withdifferent In Situ Control Mechanisms. In some embodiments, thefunctionality described below as being performed by controller module504 may be performed by one or more In Situ Control Mechanisms 506individually or in concert. In some embodiments, controller module 504may communicate with the In Situ Control Mechanisms through a devicemanager 502. In some embodiments, controller module 504 be incommunication with a user interface 508 and/or a database 510.

In some embodiments, some or all of these In-Situ Control Mechanisms 506may contain wireless communication capability to establish Wireless DataLinks to controller module 504 (e.g., through device manager 502).Wireless Data Links may operate in either a unidirectional or abidirectional manner. The network of Wireless Data Links may beimplemented using a mesh network, a star network, point-to-pointcommunication, and/or any other suitable communication technique.In-Situ Control Mechanisms 506 may send information over a communicationnetwork to a distributed network (e.g., the “cloud”). Communication mayoccur through a system including but not limited to a cell phone network(2G, 3G, 4G LTE, GSM, CDMA 1×RTT, etc.), a satellite network, a localarea network connected to the Internet, etc. In some embodiments, the InSitu Control Mechanisms 506 may communicate with each other and/or withcontroller module 504 using wired data links, Wireless Data Links, powerline communication, and/or any other suitable communication technique.

Information sent (e.g., over Wireless Data Links) by the In-Situ ControlMechanisms 506 may include but is not limited to sensor data,environmental data, failure notifications, status notifications,calibration notifications, etc. Information received by the In-SituControl Mechanisms may include but is not limited to: raw orpre-processed data about the current or past operational state of otherlandfill gas extraction wells in the landfill under control, command andcontrol signals, desired operating states, predictive calculations aboutthe operating state of the well upon which the In-Situ Control Mechanismis installed or other landfill gas extraction wells, failurenotifications, status notifications, calibration changes, softwareand/or firmware updates, flow-control mechanism settings, sensorsettings, and/or other information.

In some embodiments, In Situ Control Mechanisms 506 in the landfillunder control 520 may communicate with a Device Manager 502, asindicated in FIG. 5 , and/or they may communicate directly with eachother. The Device Manager 502 may include software operating on acomputer in the landfill under control, or operating on a remote server,and/or operating on a distributed computing network (“the cloud”) in oneor multiple locations. In some embodiments, Device Manager 502 may beimplemented using a computing system 1100 as described below. The DeviceManager 502 may collect information from alternate sources—including butnot limited to environmental data, past history about electrical powerdemand and/or prices, forecasts about future electrical power demandand/or prices, etc. In some embodiments, the Device Manager 502 may bein constant communication with the In-Situ Control Mechanisms 506, or itmay communicate asynchronously with the In-Situ Control Mechanisms. Insome embodiments, the Device Manager 502 may hold a queue of commands orother information to be passed to the In Situ Control Mechanism(s) 506upon the establishment of a data link (e.g., re-establishment of aWireless Data Link).

In some embodiments, the Device Manager 502 may associate a set ofIn-Situ Control Mechanisms 506 into a single landfill under control 520,and it may add or remove additional In-Situ Control Mechanisms 506 tothat landfill under control 520 to accommodate the addition or removalof In-Situ Control Mechanisms from the site. The Device Manager 502 maycontain or perform authentication or encryption procedures uponestablishing a data link (e.g., a Wireless Data Link) with an In-SituControl Mechanism. Security protocols implemented by the Device Managermay include, but are not limited to: internet key exchange, IPsec,Kerberos, point to point protocols, transport layer security (TLS),HTTPS, SSH, SHTP, etc.

In some embodiments, the Device Manager 502 may communicate with acontroller module 504. The controller module 504 may include one or moreapplications running on a distributed computational platform (e.g., a“cloud server”), a traditional server infrastructure, a computing system1100 as described below, and/or other suitable computer architecturerecognized by those of ordinary skill in the art. It should beappreciated, however, that control functions as described herein may bedistributed across device manager 502, controller module 504 and/or anyother computing components in any suitable way. Similarly, controlfunctions may be distributed across processors (e.g., controllers)associated with one or more In Situ Control Mechanisms.

In some embodiments, control system 500 may be configured to predictfuture states of the landfill under control, and/or may be configured touse such predictions to control the operation of a gas extraction systemassociated with the landfill under control. In some embodiments, usingone or more predictions regarding the future state(s) of the landfillunder control to control the operation of the gas extraction system mayimprove the performance (e.g., efficiency) of the gas extraction system,relative to the performance of conventional gas extraction systems.

FIG. 6 shows a feedback-based, predictive control system 600, which maybe implemented by some embodiments of control system 500 to control theoperation of gas extraction system associated with a landfill undercontrol 620. Feedback-based, predictive control system 600 may include apredictive landfill state estimator 602 for predicting one or morefuture states of a landfill under control 620, and one or more controlmodules 605 for controlling the operation of a gas extraction system(e.g., by controlling the operation of one or more in situ controlmechanisms 606 in the landfill under control 620) based, at least inpart, on the predicted future state(s) of the landfill under control620. The predictive landfill state estimator 602 and/or controlmodule(s) 605 may be implemented by controller 504 and/or bycontroller(s) 204 of in situ control mechanism(s) 606, with thefunctions of the predictive landfill state estimator 602 and the controlmodule(s) 605 being divided among the controller 504 and the in situcontrol mechanism(s) 606 in any suitable way.

In some embodiments, predictive landfill state estimator 602 may includeone or more predictive models of the landfill under control 620. Eachmodel may relate a set of parameters defining a current state of thelandfill to one or more sets of parameters, defining one or more futurestates of the landfill. Any suitable modeling techniques may be used todevelop such a model, which may be implemented using softwareprogramming on a computing device. Different models may be selecteddepending on parameters defining input or output states. For example,different models may be used to predict parameters such as odor, energyproduction, or gas production.

In some embodiments, predictive landfill state estimator 602 may use apredictive model to predict a future state 638 of at least one attributeof a landfill under control, based on a model of the landfill undercontrol and/or based on suitable input data. In some embodiments, thepredictive landfill state estimator 602 may apply mathematical models topresent and/or past data about the landfill under control 620 (e.g.,data about landfill gas production and/or extraction) to estimate afuture state of the landfill under control (e.g., the future LFGproduction and/or extraction). Suitable input data for the predictivelandfill state estimator 602 may include the current state 634 offlow-control mechanisms in the gas extraction system of the landfillunder control (e.g., the operating states of valves in the gasextraction system), the current state 635 of the landfill under control(e.g., the characteristics of the landfill's gas, as determined usingthe in situ control mechanism's sensors), and/or environmental data 636(e.g., data describing environmental conditions in and/or around thelandfill, as determined by the in situ control mechanism's sensors orany other suitable data source). In some embodiments, the predictedfuture state may correspond to a specified date and/or time in thefuture.

In some embodiments, control module(s) 605 may control the operation ofthe gas extraction system based, at least in part, on the predictedfuture state 638 of the landfill under control. For example, controlmodule(s) 605 may determine the values of control parameters 644(“control settings”) for the in situ control mechanism(s) 606 based onthe predicted future state 638. In embodiments where the controlmodule(s) are not implemented by the in situ control mechanism(s) 606,the control module(s) may send the determined values of the controlparameters 644 to the in situ control mechanism(s) 606. The in situcontrol mechanism(s) 606 may apply the control parameters toflow-control mechanisms in the gas extraction system (e.g., valves) tocontrol the operation of the gas extraction system (e.g., the in situcontrol mechanism(s) 606 may adjust the gas extraction rate from thelandfill under control 620 by modulating the positions of valves in thegas extraction system). As another example, control module(s) 605 maydetermine changes in the current values of control parameters 644 forthe in situ control mechanisms(s) 606 based on the predicted futurestate, and the in situ control mechanism(s) may change the controlparameters of the flow-control mechanisms by the determined amounts.

In some embodiments, control module(s) 605 may determine the values (orchanges in the values) of the control parameters 644 based on predictedfuture state 638 and/or based on other input data. For example, controlmodule(s) 605 may determine a difference between a predicted and adesired future state, determine control parameters 644 to reduce thatdifference, and apply the control parameters to in situ controlmechanism(s) 606 (e.g., by controlling an in situ control mechanism toadjust a valve or other actuator in accordance with the controlparameters) to reduce that difference. The input data may include thecurrent state 634 of flow-control mechanisms in the gas extractionsystem, the current state 635 of the landfill under control, designconstraints 640, and/or set point(s) 642.

In some embodiments, design constraints 640 may include physicallimitations of the landfill gas extraction system including, but notlimited to: operating ranges of the flow-control mechanisms (e.g.,available valve movement range), accuracy of the operating states of theflow-control mechanisms (e.g., valve position accuracy), resolution ofthe operating states of the flow-control mechanisms (e.g., valveposition resolution), gas extraction system vacuum pressure, measurementranges of the in situ control mechanism(s)′ sensors, power generationcapacity at a landfill gas to energy power plant, total flow raterestrictions of the landfill gas extraction system, and/or any othersuitable limitations. In some embodiments, design constraints 640 may behard-coded values, and/or they may be specific to particular well,collection of wells, landfills, or geographic regions. In someembodiments, design constraints may be re-programmed by a human operatorthrough a software or hardware interface (for example, a webapplication, a mobile application, through manual or over the airfirmware upgrades, etc.). Control module 605 may use these designconstraints, for example, in selecting values of control parameters suchthat the design constraints are not violated.

In some embodiments, the set point(s) 642 may indicate a desiredoperating state for the gas extraction system (e.g., an energy contentextraction rate, gas flow rate, gas composition, and/or other suitablecharacteristic for the gas extraction system, for individual wells,and/or for individual in situ control mechanisms). In some embodiments,the control module(s) 605 may determine the values of the controlparameters 644 (e.g., using a mathematical model or models) to maintainthe state of the landfill under control equal to, less than, or greaterthan the set point. In this manner, the control module(s) 605 may usethe state of the landfill (e.g., the current and/or predicted states ofthe landfill) to control the gas extraction system to operate in adesired operating state (as indicated by the set point(s)), withoutviolating the system's design constraints. The set point(s) may be hardcoded into the system, may be user adjustable via a software interface(e.g., web or mobile application), and/or may be set and/or adjustedusing any other suitable technique.

Predictive landfill state estimator 602 may obtain its input data usingany suitable technique. In some embodiments, predictive landfill stateestimator 602 may obtain the current state 634 of the flow-controlmechanisms in the gas extraction system and/or the current state 635 ofthe landfill from the in situ control mechanism(s) 606 (e.g., byquerying the in situ control mechanism(s) 606 via the Device Manager).

FIG. 7 shows a feedback-based, predictive control system 700, which maybe implemented by some embodiments of control system 500 to control theoperation of gas extraction system associated with a landfill undercontrol 620. In some embodiments, feedback-based, predictive controlsystem 700 may be adaptive (“self-learning”). In some embodiments of theadaptive control system 700, the predictive landfill state estimator 702may compare the current state 635 of the landfill (e.g., the currentstate of landfill gas production) to the previously predicted state 738of the landfill, and modify parameters in the state estimator's stateestimation model or models to make the predicted states more closelymatch the actual measured states. In this manner, the accuracy of thestate estimator's predictions may improve over time, and/or the stateestimator may adapt to changing conditions over time, so that the stateestimator's predictions remain accurate even as the conditions in andaround the landfill change.

In some embodiments, adaptive control system 700 may include apredictive landfill state estimator 702, a state comparator 750, and amodel adapter 752. In some embodiments, predictive landfill stateestimator 702 may include one or more predictive models of the landfillunder control 620, and may apply the predictive model(s) to suitableinput data (e.g., current state 634 of flow-control mechanisms, currentstate 635 of the landfill under control, and/or environmental data 636)to predict one or more future states 738 of the landfill under control.

In some embodiments, state comparator 750 and model adapter 752 mayadapt the state estimator's predictive model(s) to improve the accuracyof the predictive model(s). In some embodiments, state comparator 750may compare a predicted future state 738 of the landfill and asubsequently measured current state 635 of the landfill. In someembodiments, model adapter 752 may use the difference 760 between thepredicted state and the actual state of the landfill to determinemodified parameter values 762 for one or more parameters in the stateestimator's predictive model(s), to improve (e.g., continually improve)the accuracy of those models.

In some embodiments, the modified parameter values 762 output by themodel adapter 752 may act to reduce the difference between the predictedfuture state of the landfill (if it were recalculated using the modifiedparameter values) and the actual current state of the landfill (e.g., toreduce the difference to zero). In some embodiments, the modifiedparameter values 762 may act to reduce (e.g., minimize) another errormetric (e.g., to reduce the mean error, the sum of the squares of errorsfor one or more (e.g., all) previous predictions, and/or any othermetric). The modified parameter values 762 may be output after everycycle of the feedback loop, or they may be selectively applied. In someembodiments, the model adapter 752 may detect anomalous data points inthe measured current state 635 of the landfill (as may happen, e.g.,during natural events (e.g., extreme weather), during equipmentmalfunction (e.g., sensor or control valve failures), when theoperations of the Landfill Gas to Energy plant are suddenly disrupted,etc.). In some embodiments, control system 700 may not apply modifiedparameter values 762 to the predictive model(s) of the predictivelandfill state estimator 702 during such events.

In some embodiments, adaptive control system 700 may also include one ormore control module(s) 605 and one or more in situ control mechanism(s)606, which may control the operation of a gas extraction systemassociated with landfill under control 620. Some embodiments of controlmodule(s) 605 and in situ control mechanism(s) 606 are described abovewith reference to FIG. 6 . For brevity, these descriptions are notrepeated here.

Returning to the control system 500 shown in FIG. 5 , in someembodiments the controller module 504 may be in communication with adatabase 510 and/or a user interface 508. In some embodiments, thedatabase 510 may be implemented on a centralized storage mechanism (harddrive, disk drive, or some other non-volatile memory), or it may resideon a distributed storage mechanism (e.g., a cloud server, or any othersuitable distributed storage device). The database 510 may serve as along term archive of historical data and/or past predictions from thepredictive landfill state estimator 602, and/or may store past designconstraints 640, current design constraints 640, past set points 642,current set points 642, any parameters from the state estimator'spredictive model(s), any parameters from the flow-control mechanisms,and/or any other data (for example, environmental data, data fromlandfill operations, etc.). In some embodiments, the data stored indatabase 510 may be used to train predictive landfill state estimator702. In some embodiments, the data stored in database 510 may beprovided as input data to the predictive landfill state estimator, whichmay use the data to predict the next state of the landfill undercontrol. In some embodiments, the data stored in database 510 may beprovided as input data to the control module(s) 605 and may be used todetermine the values of control parameters 644. The database may beimplemented using MySQL, dBASE, IBM DB2, LibreOffice Base, Oracle, SAP,Microsoft SQL Server, MariaDB, SQLite, FoxPro, and/or any othercommercially available database management software that will berecognized by one of ordinary skill in the art. In some embodiments, thedatabase may be of a custom construction.

In some embodiments, the controller module 504 may display certain dataand/or accept inputs via a user interface 508. In some embodiments, theuser interface 508 may include a web site, may include a mobileapplication (tablet, phone, or other mobile device), and/or may beprovided through a terminal via a local network (e.g., secure localnetwork) operating at the landfill under control. The user interface maydisplay current and/or historical gas extraction data collected from aparticular well or any set of wells in a given landfill. The userinterface may display data via tables, charts, graphs, and/or any othersuitable technique, and may do so over various periods of time (e.g.,the previous day, past week, past month, etc.). The user interface mayoverlay data from wells in a given landfill on top of or embedded intoaerial maps or renderings of the landfill, and/or it may display dataoverlays with topographical maps, schematics of the underground pipingsystem, and/or other engineering drawings.

In some embodiments, the user interface may allow users to click on aparticular well or set of wells and manually adjust set points, designconstraints, and/or other parameters of the control system 500 as theypertain to those wells. The user interface may allow users to set alarmsor notifications if gas extraction data or gas data from wells undercontrol cross certain thresholds as defined by the user (for example, auser may request an email or SMS message to be sent in the event thatgas from any well exceeds 55% methane or drops below 45% methane byvolume, and/or a user may set an alarm if gas temperature rises above120 degrees Fahrenheit at any well, etc.).

In some embodiments, control modules 605 corresponding to two or more InSitu Control Mechanisms 606 may be in communication with each other(e.g., control modules 605 may be implemented by controller 504 andshare data through the memory of controller 504, and/or control modules605 may be implemented by the corresponding In Situ Control Mechanisms,which may communicate with each other directly or through controller504). The control parameters 644 for a given In Situ Control Mechanism606 may then be determined in accordance with, and/or driven by, thebehavior, control parameters, sensor readings, and/or other data ofother In Situ Control Mechanisms in the landfill under control (e.g., inthe surrounding area). Such interdependence among the control parameters644 of the in situ control mechanisms 606 may improve the performance ofthe gas extraction system, because adjustments to each gas extractionpoint, being in fluid communication in the trash, and/or in fluidcommunication through the gas extraction piping system, may influencethe surrounding areas. The spatial area around a given landfill gasextraction well that is affected by that well is called its' “Zone ofInfluence.”

FIG. 8 depicts the Zones of Influence 804 a-c around a set of severalgas extraction wells 802 a-c. In this example, well 802 c hasoverlapping zones of influence 806 with both other wells. In such anexample, changes to the gas extraction rate at well 802 c will impactthe gas characteristics at wells 802 a and 802 b. In some embodiments ofthe landfill gas extraction control system disclosed herein, oneobjective of the processing performed by the state estimator and/orcontrol module(s) 605 may be to identify such overlapping zones ofinfluence and incorporate interactions between wells into their models.

The inventors have recognized and appreciated that as the porosity ofwaste in a landfill varies (due to heterogeneous waste composition andcompaction at the time of dumping, and also due to the naturaldecomposition of waste over time and settling effects), certain wellsmay have highly irregular zones of influence 904 a-b as depicted in FIG.9 below. By placing a set of In-Situ Control Mechanisms on adjacentwells in a landfill, it may be possible to quantify and model thestrength of interactions between individual wells and to create aninteraction matrix that captures an effective “coupling parameter”between any two or more wells in that landfill. In some embodiments, thecoupling parameters and/or the interaction matrix may be used to developor improve the model(s) of the state estimator and/or control module(s)605 in the control system, and/or may be used to inform the placement ofadditional wells (e.g., in areas of the landfill where gas extractionmay be lacking with the existing wells).

The techniques and devices disclosed herein may be used to modulate therate of gas extraction of a well or set of wells in accordance with anysuitable control scheme, including but not limited to:

-   -   Modulation of the gas extraction rate to control vacuum pressure        (e.g., maintain and/or obtain a constant vacuum pressure) in the        landfill and/or wells under control (in spite of varying        atmospheric pressure, temperature, and/or varying rates of gas        generation, etc.);    -   Modulation of the gas extraction rate to maintain and/or obtain        a constant flow rate of landfill gas from the landfill and/or        wells under control;    -   Modulation of the gas extraction rate to control (e.g., increase        or decrease) the flow rate of landfill gas from the landfill        and/or wells under control;    -   Modulation of the gas extraction rate to maintain and/or obtain        a constant percentage of any of the constituent gases (including        but not limited to methane, carbon dioxide, oxygen, nitrogen,        etc.) in the landfill gas coming from the landfill and/or wells        under control;    -   Modulation of the gas extraction rate to control (e.g., increase        or decrease) the concentration of any of the constituent gases        in the landfill gas coming from the landfill or wells under        control;    -   Modulation of the gas extraction rate to control (e.g., increase        or decrease) the energy content of the landfill gas (e.g.,        control the total quantity of methane extracted in a given        period of time, etc.) coming from the landfill and/or wells        under control;    -   Modulation of the gas extraction rate to control (e.g., increase        or decrease) the total volume of the landfill gas (e.g., control        the total quantity of landfill gas extracted in a given period        of time, etc.) coming from the landfill and/or wells under        control;    -   Modulation of the gas extraction rate to increase the rate of        extraction during periods of increased energy demand (e.g.,        increasing generation during the peaks of real time, hourly,        daily, weekly, monthly, and/or seasonal electricity prices);    -   Modulation of the gas extraction rate to decrease the rate of        extraction during periods of reduced energy demand (e.g.,        reducing generation during the lows of real time, hourly, daily,        weekly, monthly, or seasonal electricity prices);    -   Modulation of the gas extraction rate to control (e.g.,        maintain, improve, and/or establish) the long term stability of        the biochemical decomposition processes (aerobic or anaerobic        digestion, etc.) occurring within a section of waste that is in        the vicinity of the well(s) under control;    -   Modulation of the gas extraction rate to control (e.g., increase        or decrease) the rates of decomposition occurring within a        section of waste that is in the vicinity of the well(s) under        control;    -   Modulation of the gas extraction rate to match the operating        parameters or limitations of the gas collection system for the        landfill and/or wells under control (including limitations of        header junctions and/or subsections of underground piping that        impact only certain wells);    -   Modulation of the gas extraction rate to prevent or extinguish        underground fires and/or other potentially dangerous events        occurring within a section of waste that is in the vicinity of        the well(s) under control;    -   Modulation of the gas extraction rate to control (e.g., reduce)        emission of odors from the landfill and/or wells under control;    -   Modulation of the gas extraction rate to control (e.g., reduce)        emissions of landfill gas or components of landfill gas (H₂S,        methane, etc.) in the vicinity of the gas extraction well(s)        under control;    -   Modulation of the gas extraction rate to control (e.g., reduce)        gas losses into the atmosphere;    -   Modulation of the gas extraction rate to control (e.g.,        maintain, improve, and/or establish) compliance of the gas        extraction system with local, state and/or federal regulations;    -   Modulation of the gas extraction rate to control (e.g., reduce)        damage to an engine, turbine, and/or other energy generation        equipment from contaminants emanating from the vicinity of a        well or wells under control;

The success or failure of the above-described control schemes may beassessed in any suitable way. In some embodiments, attributes of thelandfill gas may be monitored over a period of time, and a determinationmay be made as to whether the monitored values comply with the controlscheme. For example, to determine whether a specified quantity ofmethane has been extracted from the landfill in a specified time period,the concentration of methane in the extracted landfill gas and the flowrate of the extracted landfill gas may be monitored during the timeperiod, and quantity of extracted methane may be determined based on themonitored methane concentration levels and gas flow rates. In someembodiments, attributes of the landfill gas may be measured at aspecified time, and a determination may be made as to whether themeasured values comply with the control scheme. For example, todetermine whether the flow rate of extracted landfill gas matches atarget flow rate, the flow rate of extracted landfill gas may bemeasured at some time and compared to the target flow rate.

In some embodiments, the control system 500 may be used to monitor theeffect of other treatments besides just the setting of the control valve(e.g., monitoring effects of microbial treatment, leachaterecirculation, watering out/pumping of the wells, adding iron, H₂Sabatement, etc.).

FIG. 10 illustrates a method 1000 for control extraction of landfill gasfrom a landfill through a gas extraction system, according to someembodiments. In step 1002 of method 1000, values indicating conditionsassociated with the landfill are measured. In step 1004 of method 1000,a future state of the landfill is predicted based, at least in part, onthe measured values and on the model of the landfill. In someembodiments, the predicted future state may be computed by at least onecomputing device. In step 1006 of method 1000, one or more controlparameters are determined for one or more control devices configured tocontrol operation of the landfill's gas extraction system. In step 1008of method 1000, the control parameter(s) are applied to the controldevice(s) of the gas extraction system. In step 1010 of method 1000,extraction of the landfill gas is controlled (e.g., by the one or morecontrol devices) based, at least in part, on the control parameter(s).

In some embodiments, the predicted future state of the landfill mayinclude one or more predicted attributes of the landfill gas produced bythe landfill and/or extracted by the gas extraction system at a futuretime and/or in a future time period. In some embodiments, the futurestate of the landfill may be predicted based, at least in part, on thepredicted future state of the landfill, on the model of the landfill, onthe current state of the landfill, on control parameter(s) applied tothe control device(s) before making the prediction, and/or onenvironmental data indicating environmental conditions associated withthe landfill. In some embodiments, the current state of the landfill mayinclude the measured values indicating conditions associated with thelandfill. In some embodiments, the measured values may be measured bysensor devices (e.g., sensor devices associated with one or more in situcontrol mechanisms). The values indicating conditions associated withthe landfill may include temperature, pressure, flow rate, humidity,density, and/or composition of the landfill gas. In some embodiments,the determined attributes may correspond to landfill gas provided by asingle well, landfill gas provided by a plurality of wells, and/orlandfill gas extracted from the landfill. In some embodiments, theenvironmental data may indicate atmospheric pressure, ambienttemperature, wind direction, wind speed, characteristics of ambientprecipitation, subsurface temperature, subsurface moisture level, and/orpH value of an area of the landfill or adjacent to the landfill.

In some embodiments, the one or more control parameters may bedetermined based, at least in part, on predicted future electrical powerdemand and/or on an energy content of the landfill gas extracted fromthe landfill. In some embodiments, the one or more control parametersmay be applied to the one or more respective control devices in realtime. In some embodiments, controlling extraction of the landfill gasfrom the landfill may include controlling a flow rate and/or compositionof the landfill gas extracted from the landfill. In some embodiments,the control parameter(s) may be determined based, at least in part, onthe predicted future state of the landfill, on a current state of thelandfill, on one or more current values of the control parameters,and/or on a control objective for the landfill. In some embodiments, thecontrol parameter(s) may be determined based, at least in part, onelectrical power data including past electrical power consumption, pastelectrical power prices, predicted future electrical power demand,and/or predicted future electrical power prices. In some embodiments,the control parameter(s) may be determined based, at least in part, on atarget rate at which the landfill gas is extracted from the landfill bythe gas extraction system, a target vacuum pressure applied to the gasextraction system, a target composition of the landfill gas extractedfrom the landfill by the gas extraction system, a target energy contentof the landfill gas extracted from the landfill by the gas extractionsystem, a target volume of the landfill gas extracted from the landfillby the gas extraction system, a target stability of a decompositionprocess in the landfill, a target rate of a decomposition process in thelandfill, a target rate of emission of the landfill gas into anatmosphere, a target odor level associated with emission of the landfillgas into the atmosphere, and/or a target level of compliance with one ormore regulations applicable to the landfill.

Although not illustrated in FIG. 10 , some embodiments of method 1000may include one or more steps for adapting the predictive model(s) ofthe predictive landfill state estimator. In some embodiments, such stepsmay include (1) after computing the predicted future state of thelandfill at the future time, determining an actual state of the landfillat the future time, and (2) adapting the model based, at least in part,on a difference between the predicted future state of the landfill andthe determined actual state of the landfill. In some embodiments,adapting the model may include adapting the model to decrease thedifference between the predicted future state of the landfill and thedetermined actual state of the landfill.

FIG. 11 illustrates an example of a suitable computing systemenvironment 1100 on which techniques disclosed herein may beimplemented. In some embodiments, portions of a landfill gas extractioncontrol system may be implemented in a computing system environment. Forexample, in some embodiments, Device Manager 502, Controller Module 504,User Interface 508, and/or Database 510 may be implemented in acomputing system environment. In some embodiments, aspects of one ormore techniques describes herein may be implemented in a computingsystem environment.

The computing system environment 1100 is only one example of a suitablecomputing environment and is not intended to suggest any limitation asto the scope of use or functionality of the devices and techniquesdisclosed herein. Neither should the computing environment 1100 beinterpreted as having any dependency or requirement relating to any oneor combination of components illustrated in the exemplary operatingenvironment 1100.

The techniques disclosed herein are operational with numerous othergeneral purpose or special purpose computing system environments orconfigurations. Examples of well-known computing systems, environments,and/or configurations that may be suitable for use with techniquesdisclosed herein include, but are not limited to, personal computers,server computers, hand-held devices (e.g., smart phones, tabletcomputers, or mobile phones), laptop devices, multiprocessor systems,microprocessor-based systems, set top boxes, programmable consumerelectronics, network PCs, minicomputers, mainframe computers,distributed computing environments that include any of the above systemsor devices, and the like.

The computing environment may execute computer-executable instructions,such as program modules. Generally, program modules include routines,programs, objects, components, data structures, etc. that performparticular tasks or implement particular abstract data types. Theinvention may also be practiced in distributed computing environmentswhere tasks are performed by remote processing devices that are linkedthrough a communications network. In a distributed computingenvironment, program modules may be located in both local and remotecomputer storage media including memory storage devices.

With reference to FIG. 11 , an exemplary system for implementingtechniques described herein includes a general purpose computing devicein the form of a computer 1110. Components of computer 1110 may include,but are not limited to, a processing unit 1120, a system memory 1130,and a system bus 1121 that couples various system components includingthe system memory to the processing unit 1120. The system bus 1121 maybe any of several types of bus structures including a memory bus ormemory controller, a peripheral bus, and/or a local bus using any of avariety of bus architectures. By way of example, and not limitation,such architectures include Industry Standard Architecture (ISA) bus,Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, VideoElectronics Standards Association (VESA) local bus, and PeripheralComponent Interconnect (PCI) bus also known as Mezzanine bus.

Computer 1110 typically includes a variety of computer readable media.Computer readable media can be any available media that can be accessedby computer 1110 and includes both volatile and nonvolatile media,removable and non-removable media. By way of example, and notlimitation, computer readable media may comprise computer storage mediaand communication media. Computer storage media includes both volatileand nonvolatile, removable and non-removable media implemented in anymethod or technology for storage of information such as computerreadable instructions, data structures, program modules or other data.Computer storage media includes, but is not limited to, RAM, ROM,EEPROM, flash memory or other memory technology, CD-ROM, digitalversatile disks (DVD) or other optical disk storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other medium which can be used to store the desired informationand which can accessed by computer 1110. Communication media typicallyembodies computer readable instructions, data structures, programmodules or other data in a modulated data signal such as a carrier waveor other transport mechanism and includes any information deliverymedia. The term “modulated data signal” means a signal that has one ormore of its characteristics set or changed in such a manner as to encodeinformation in the signal. By way of example, and not limitation,communication media includes wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, RF,infrared and other wireless media. Combinations of the any of the aboveshould also be included within the scope of computer readable media.

The system memory 1130 includes computer storage media in the form ofvolatile and/or nonvolatile memory such as read only memory (ROM) 1131and random access memory (RAM) 1132. A basic input/output system 1133(BIOS), containing the basic routines that help to transfer informationbetween elements within computer 1110, such as during start-up, istypically stored in ROM 1131. RAM 1132 typically contains data and/orprogram modules that are immediately accessible to and/or presentlybeing operated on by processing unit 1120. By way of example, and notlimitation, FIG. 11 illustrates operating system 1134, applicationprograms 1135, other program modules 1136, and program data 1137.

The computer 1110 may also include other removable/non-removable,volatile/nonvolatile computer storage media. By way of example only,FIG. 11 illustrates a hard disk drive 1141 that reads from or writes tonon-removable, nonvolatile magnetic media, a magnetic disk drive 1151that reads from or writes to a removable, nonvolatile magnetic disk1152, and an optical disk drive 1155 that reads from or writes to aremovable, nonvolatile optical disk 1156 such as a CD ROM or otheroptical media. Other removable/non-removable, volatile/nonvolatilecomputer storage media that can be used in the exemplary operatingenvironment include, but are not limited to, magnetic tape cassettes,flash memory cards, digital versatile disks, digital video tape, solidstate RAM, solid state ROM, and the like. The hard disk drive 1141 istypically connected to the system bus 1121 through an non-removablememory interface such as interface 1140, and magnetic disk drive 1151and optical disk drive 1155 are typically connected to the system bus1121 by a removable memory interface, such as interface 1150.

The drives and their associated computer storage media discussed aboveand illustrated in FIG. 11 , provide storage of computer readableinstructions, data structures, program modules and other data for thecomputer 1110. In FIG. 11 , for example, hard disk drive 1141 isillustrated as storing operating system 1144, application programs 1145,other program modules 1146, and program data 1147. Note that thesecomponents can either be the same as or different from operating system1134, application programs 1135, other program modules 1136, and programdata 1137. Operating system 1144, application programs 1145, otherprogram modules 1146, and program data 1147 are given different numbershere to illustrate that, at a minimum, they are different copies. A usermay enter commands and information into the computer 1110 through inputdevices such as a keyboard 1162 and pointing device 1161, commonlyreferred to as a mouse, trackball or touch pad. Other input devices (notshown) may include a microphone, joystick, game pad, satellite dish,scanner, or the like. These and other input devices are often connectedto the processing unit 1120 through a user input interface 1160 that iscoupled to the system bus, but may be connected by other interface andbus structures, such as a parallel port, game port or a universal serialbus (USB). A monitor 1191 or other type of display device is alsoconnected to the system bus 1121 via an interface, such as a videointerface 1190. In addition to the monitor, computers may also includeother peripheral output devices such as speakers 1197 and printer 1196,which may be connected through a output peripheral interface 1195.

The computer 1110 may operate in a networked environment using logicalconnections to one or more remote computers, such as a remote computer1180. The remote computer 1180 may be a personal computer, a server, arouter, a network PC, a peer device or other common network node, andtypically includes many or all of the elements described above relativeto the computer 1110, although only a memory storage device 1181 hasbeen illustrated in FIG. 11 . The logical connections depicted in FIG.11 include a local area network (LAN) 1171 and a wide area network (WAN)1173, but may also include other networks. Such networking environmentsare commonplace in offices, enterprise-wide computer networks, intranetsand the Internet.

When used in a LAN networking environment, the computer 1110 isconnected to the LAN 1171 through a network interface or adapter 1170.When used in a WAN networking environment, the computer 1110 typicallyincludes a modem 1172 or other means for establishing communicationsover the WAN 1173, such as the Internet. The modem 1172, which may beinternal or external, may be connected to the system bus 1121 via theuser input interface 1160, or other appropriate mechanism. In anetworked environment, program modules depicted relative to the computer1110, or portions thereof, may be stored in the remote memory storagedevice. By way of example, and not limitation, FIG. 11 illustratesremote application programs 1185 as residing on memory device 1181. Itwill be appreciated that the network connections shown are exemplary andother means of establishing a communications link between the computersmay be used.

Embodiments of the above-described techniques can be implemented in anyof numerous ways. For example, the embodiments may be implemented usinghardware, software or a combination thereof. When implemented insoftware, the software code can be executed on any suitable processor orcollection of processors, whether provided in a single computer ordistributed among multiple computers. In some embodiments, the functionsperformed by an In Situ Control Mechanism 106 and/or a Controller 204may be implemented as software executed on one or more processors.

Such processors may be implemented as integrated circuits, with one ormore processors in an integrated circuit component, includingcommercially available integrated circuit components known in the art bynames such as CPU chips, GPU chips, microprocessor, microcontroller, orco-processor. Alternatively, a processor may be implemented in customcircuitry, such as an ASIC, or semicustom circuitry resulting fromconfiguring a programmable logic device. As yet a further alternative, aprocessor may be a portion of a larger circuit or semiconductor device,whether commercially available, semi-custom or custom. As a specificexample, some commercially available microprocessors have multiple coressuch that one or a subset of those cores may constitute a processor.Though, a processor may be implemented using circuitry in any suitableformat.

Further, it should be appreciated that a computer may be embodied in anyof a number of forms, such as a rack-mounted computer, a desktopcomputer, a laptop computer, or a tablet computer. Additionally, acomputer may be embedded in a device not generally regarded as acomputer but with suitable processing capabilities, including a PersonalDigital Assistant (PDA), a smart phone or any other suitable portable orfixed electronic device.

Also, a computer may have one or more input and output devices. Thesedevices can be used, among other things, to present a user interface.Examples of output devices that can be used to provide a user interfaceinclude printers or display screens for visual presentation of outputand speakers or other sound generating devices for audible presentationof output. Examples of input devices that can be used for a userinterface include keyboards, and pointing devices, such as mice, touchpads, and digitizing tablets. As another example, a computer may receiveinput information through speech recognition or in other audible format.

Such computers may be interconnected by one or more networks in anysuitable form, including as a local area network or a wide area network,such as an enterprise network or the Internet. Such networks may bebased on any suitable technology and may operate according to anysuitable protocol and may include wireless networks, wired networks orfiber optic networks.

Also, the various methods or processes outlined herein may be coded assoftware that is executable on one or more processors that employ anyone of a variety of operating systems or platforms. Additionally, suchsoftware may be written using any of a number of suitable programminglanguages and/or programming or scripting tools, and also may becompiled as executable machine language code or intermediate code thatis executed on a framework or virtual machine.

In this respect, the invention may be embodied as a computer readablestorage medium (or multiple computer readable media) (e.g., a computermemory, one or more floppy discs, compact discs (CD), optical discs,digital video disks (DVD), magnetic tapes, flash memories, circuitconfigurations in Field Programmable Gate Arrays or other semiconductordevices, or other tangible computer storage medium) encoded with one ormore programs that, when executed on one or more computers or otherprocessors, perform methods that implement the various embodiments ofthe invention discussed above. As is apparent from the foregoingexamples, a computer readable storage medium may retain information fora sufficient time to provide computer-executable instructions in anon-transitory form. Such a computer readable storage medium or mediacan be transportable, such that the program or programs stored thereoncan be loaded onto one or more different computers or other processorsto implement various aspects of the present invention as discussedabove. As used herein, the term “computer-readable storage medium”encompasses only a computer-readable medium that can be considered to bea manufacture (i.e., article of manufacture) or a machine. Alternativelyor additionally, the invention may be embodied as a computer readablemedium other than a computer-readable storage medium, such as apropagating signal.

The terms “program” or “software” are used herein in a generic sense torefer to any type of computer code or set of computer-executableinstructions that can be employed to program a computer or otherprocessor to implement various aspects of the present invention asdiscussed above. Additionally, it should be appreciated that accordingto one aspect of this embodiment, one or more computer programs thatwhen executed perform methods of the present invention need not resideon a single computer or processor, but may be distributed in a modularfashion amongst a number of different computers or processors toimplement various aspects of the present invention.

Computer-executable instructions may be in many forms, such as programmodules, executed by one or more computers or other devices. Generally,program modules include routines, programs, objects, components, datastructures, etc. that perform particular tasks or implement particularabstract data types. Typically the functionality of the program modulesmay be combined or distributed as desired in various embodiments.

Also, data structures may be stored in computer-readable media in anysuitable form. For simplicity of illustration, data structures may beshown to have fields that are related through location in the datastructure. Such relationships may likewise be achieved by assigningstorage for the fields with locations in a computer-readable medium thatconveys relationship between the fields. However, any suitable mechanismmay be used to establish a relationship between information in fields ofa data structure, including through the use of pointers, tags or othermechanisms that establish relationship between data elements.

Various aspects of the present invention may be used alone, incombination, or in a variety of arrangements not specifically discussedin the embodiments described in the foregoing and is therefore notlimited in its application to the details and arrangement of componentsset forth in the foregoing description or illustrated in the drawings.For example, aspects described in one embodiment may be combined in anymanner with aspects described in other embodiments.

Also, the invention may be embodied as a method, of which an example hasbeen provided. The acts performed as part of the method may be orderedin any suitable way. Accordingly, embodiments may be constructed inwhich acts are performed in an order different than illustrated, whichmay include performing some acts simultaneously, even though shown assequential acts in illustrative embodiments.

Various events/acts are described herein as occurring or being performedat a specified time. One of ordinary skill in the art would understandthat such events/acts may occur or be performed at approximately thespecified time.

Use of ordinal terms such as “first,” “second,” “third,” etc., in theclaims to modify a claim element does not by itself connote anypriority, precedence, or order of one claim element over another or thetemporal order in which acts of a method are performed, but are usedmerely as labels to distinguish one claim element having a certain namefrom another element having a same name (but for use of the ordinalterm) to distinguish the claim elements.

Also, the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having,” “containing,” “involving,” andvariations thereof herein, is meant to encompass the items listedthereafter and equivalents thereof as well as additional items.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated that various alterations,modifications, and improvements will readily occur to those skilled inthe art.

Such alterations, modifications, and improvements are intended to bepart of this disclosure, and are intended to be within the spirit andscope of the invention. Further, though advantages of the presentinvention are indicated, it should be appreciated that not everyembodiment of the invention will include every described advantage. Someembodiments may not implement any features described as advantageousherein and in some instances. Accordingly, the foregoing description anddrawings are by way of example only.

What is claimed is:
 1. A system for monitoring extraction of landfillgas from a landfill via a gas extraction system, the system comprising:a gas analysis sample chamber having at least one sensor disposedtherein; at least one valve coupled to the gas analysis sample chamberand well piping of the gas extraction system, the at least one valveconfigured to allow gas to flow from the well piping to the gas analysissample chamber; and at least one controller configured to: automaticallyopen, at scheduled time intervals, the at least one valve to allow gasto flow from the well piping to the gas analysis sample chamber; afterautomatically opening the at least one valve to allow gas to flow fromthe well piping to the gas analysis sample chamber, automatically openthe at least one valve to allow ambient air to flow from an ambient airsource to the gas analysis sample chamber; obtain, based on at least onemeasurement made by the at least one sensor, a measure of at least onecharacteristic of landfill gas being extracted from the landfill;determine whether the measure of the at least one characteristic of thelandfill gas being extracted from the landfill is greater than an upperthreshold or less than a lower threshold; and generate a notificationwhen it is determined that the measure of the at least onecharacteristic of landfill gas being extracted from the landfill isgreater than the upper threshold or less than the lower threshold. 2.The system of claim 1, wherein generating the notification comprisestransmitting the notification.
 3. The system of claim 1, wherein thenotification comprises an alarm.
 4. The system of claim 1, wherein themeasure of the at least one characteristic of the landfill gas beingextracted from the landfill comprises a measure of a temperature of thelandfill gas being extracted from the landfill.
 5. The system of claim1, wherein the measure of the at least one characteristic of thelandfill gas being extracted from the landfill comprises a measure of avacuum pressure in the well piping.
 6. The system of claim 1, whereinthe measure of the at least one characteristic of the landfill gas beingextracted from the landfill comprises a measure of nitrogenconcentration of the landfill gas being extracted from the landfill. 7.The system of claim 1, wherein the measure of the at least onecharacteristic of the landfill gas being extracted from the landfillcomprises a measure of methane concentration of the landfill gas beingextracted from the landfill.
 8. The system of claim 7, wherein the upperthreshold is 55%.
 9. The system of claim 7, wherein the lower thresholdis 45%.
 10. The system of claim 1, wherein the measure of the at leastone characteristic of the landfill gas being extracted from the landfillcomprises a measure of oxygen concentration of the landfill gas beingextracted from the landfill.
 11. The system of claim 1, wherein the atleast one controller is configured to automatically open the at leastone valve to allow gas to flow from the well piping to the gas analysissample chamber at least once per day.
 12. The system of claim 1, whereinthe at least one controller is configured to automatically open the atleast one valve to allow gas to flow from the well piping to the gasanalysis sample chamber at least once per hour.
 13. The system of claim1, wherein the at least one controller is located remotely from the atleast one sensor and is configured to wirelessly communicate with the atleast one sensor.
 14. The system of claim 1, wherein the at least onevalve comprises a first valve coupled to the well piping and a secondvalve coupled to the ambient air source.
 15. The system of claim 1,further comprising a pump coupled to the gas analysis sample chamber.16. A method performed by at least one controller for monitoringextraction of landfill gas from a landfill via a gas extraction systemcomprising a gas analysis sample chamber having at least one sensordisposed therein, the method comprising: automatically opening, atscheduled time intervals, at least one valve coupled to the gas analysissample chamber and well piping to allow gas to flow from the well pipingto the gas analysis sample chamber; after automatically opening the atleast one valve to allow gas to flow from the well piping to the gasanalysis sample chamber, automatically opening the at least one valve toallow ambient air to flow from an ambient air source to the gas analysissample chamber; obtaining, based on at least one measurement made by theat least one sensor, a measure of at least one characteristic oflandfill gas being extracted from the landfill; determining whether themeasure of the at least one characteristic of landfill gas beingextracted from the landfill is greater than an upper threshold or lessthan a lower threshold; and generating a notification when it isdetermined that the measure of the at least one characteristic of thelandfill gas being extracted from the landfill is greater than the upperthreshold or less than the lower threshold.
 17. The method of claim 16,wherein generating the notification comprises transmitting thenotification.
 18. The method of claim 16, wherein the notificationcomprises an alarm.
 19. The method of claim 16, wherein the measure ofthe at least one characteristic of the landfill gas being extracted fromthe landfill comprises a measure of a temperature of the landfill gasbeing extracted from the landfill, a measure of a vacuum pressure in thewell piping, a measure of nitrogen concentration of the landfill gasbeing extracted from the landfill, a measure of methane concentration ofthe landfill gas being extracted from the landfill, and/or a measure ofoxygen concentration of the landfill gas being extracted from thelandfill.
 20. The method of claim 16, wherein the automatically openingthe at least one valve to allow gas to flow from the well piping to thegas analysis sample chamber is performed at least once per day.
 21. Themethod of claim 16, wherein the automatically opening the at least onevalve to allow gas to flow from the well piping to the gas analysissample chamber is performed at least once per hour.
 22. The method ofclaim 16, wherein the at least one controller is located remotely fromthe at least one sensor and is configured to wirelessly communicate withthe at least one sensor to obtain the measure of the at least onecharacteristic of the landfill gas being extracted from the landfill.